On food and cooking the science and lore of the kitchen ( PDFDrive ) 1480
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employingenoughoiltoimmersethefood
altogether.Asatechnique,itresembles
boilingmorethanpanfrying,withthe
essentialdifferencethattheoilisheatedfar
abovetheboilingpointofwater,andsowill
dehydratethefoodsurfaceandbrownit.
Microwaving:
MicrowaveRadiation
Microwaveovenstransferheatvia
electromagneticradiation,butwithwavesthat
carryonlyaten-thousandththeenergyof
infraredradiationfromglowingcoals.This
shiftmakesforauniqueheatingeffect.
Whereasinfraredwavesareenergeticenough
toincreasethevibratorymovementofnearly
allmolecules,microwavestendtoaffectonly
polarmolecules(p.793),whoseelectrical
imbalancegivestheradiationakindofhandle
withwhichtomovethem.Sofoodsthat
containwaterareheateddirectlyandrapidly
bymicrowaves.Buttheovenair,composedof
nonpolarnitrogen,oxygen,andhydrogen
molecules,andnonpolarcontainermaterials
likeglass,stoneware,andplastic(madeof
hydrocarbonchains),areunaffectedbythe
microwaves;thefoodheatsthemasitheats
up.
Here’showamicrowaveovenworks.A
transmitter,verymuchlikearadio
transmitter,setsupanelectromagneticfield
intheovenwhichreversesitspolaritysome2
or5billiontimeseverysecond.(Itoperatesat
afrequencyofeither915or2,450million
cyclespersecond,comparedtowallsocket
currentsat60cycles,andFMradiosignalsat
some100millioncyclespersecond.)Polar
watermoleculesinthefoodarepulledbythe
fieldtoorientthemselveswithit,butbecause
thefieldisconstantlychanging,themolecules
oscillatebackandforthwithit.Thewater
transmitsthismotiontoneighboring
moleculesbyknockingintothem,andthe
